1. Field of the Invention
This invention relates to appliances for preventing airway occlusion during sleep in individuals who suffer from sleep apnea or snoring, or both. More particularly it relates to an appliance that is inserted into a user's oral cavity and connected to an external negative air pressure source. In normal operation the vacuum created by the negative air pressure urges the user's tongue and soft palate anteriorly and away from the user's posterior pharyngeal wall.
Airway occlusion during sleep produces increased airway resistance to airflow and may cause cessation of breathing (apnea) and lead to undesirable physiologic changes of hypoxemia and hypercapnia. Persons suffering from sleep apnea are at risk for systemic and pulmonary hypertension, arrhythmias leading to sudden cardiac death, and accidents due to hypersomnolence.
Airway occlusion may be caused by decline in upper airway dilator muscle tone, especially the genioglossus muscle. Redundant pharyngeal tissue and edema may be contributing factors. Sleeping on the back may exacerbate airway occlusion due to the added effect of gravity on the tongue and soft palate. Sleep apnea is most pronounced during the inspiratory phase of breathing (inhalation). In patients suffering from sleep apnea or snoring, or both, the retroglossal area is usually the most obstructed part of the airway.
2. Description of Related Art
Various devices have been developed to facilitate breathing for those suffering from airway occlusion. One such device, as disclosed in U.S. Pat. No. 4,676,240, issued to Gardy on Jun. 30, 1987, provides a mechanism which holds the tongue forward in a vacuum chamber. Another device is disclosed in U.S. Pat. No. 4,170,230, issued to Nelson on Oct. 9, 1979, which allows the user to breathe through his or her mouth without drying out the mouth. Another device, as disclosed in U.S. Pat. No. 4,198,967, issued to Dror on Apr. 22, 1980, teaches a method of holding the tongue in an unconscious or semi-conscious individual as an adjunct to resuscitation of the individual.
U.S. Pat. No. 3,370,179, issued to Williams on May 1, 1973, discloses a resuscitating apparatus which includes a tube extended down the throat of a victim in combination with a draining apparatus.
None of these inventions provides for urging the tongue and soft palate anteriorly and away from the posterior pharyngeal wall by applying a partial vacuum through a device inserted into a user's oral cavity.